With consideration of damping

bearing clearance and gear backlash nonlinearity

a translational-rotational dynamics model of gear-rotor-bearing is built based on the Lagrange equation.The dynamics equation can be non-dimensionalized and simplified to an unified matrix form.By using MATLAB/SIMULINK

the numerical simulation of gear clearance nonlinearity dynamics model is carried out.Through building the simulation model

the nonlinearity vibration research in some parameter fields is carried out

the influence of parametric variation on system steady state response is analyzed.The results indicate that when the excitation frequency is smaller

the system has a period-1

non-harmonic steady state response.As the frequency increasing

the solution bifurcates into the period-2

sub-harmonic vibration response

and then into the period-4

sub-harmonic response.Finally

the steady state response becomes chaotic.The numerical simulation result also illustrates that the bearing clearance enhances the system nonlinearity.The SIMULINK can be used for more complicated model to obtain the dynamic response

which provides a method for deeply researching on the dynamic behavior of gear nonlinear system.